Grinding machine



April 17, 1956 H. A. SILVEN GRINDING MACHINE 6 Sheets-Sheet 1 Filed Dec.1, 1953 NNN \N 0 a INVENTOR.

Y& Q HERBERT A. SILVEN BY W mm ATTUE'NEY April 17, 1956 H. A. SILVENGRINDING MACHINE 6 Sheets-Sheet 2 Filed Dec. 1 19 .lllllil l lllllATTURNE Y April 17, 1956 H. A. SlLVEN GRINDING MACHINE 6 Sheets-Sheet 5Filed Dec. 1, 1953 NM N m hux HERBERT A. SILVEN BY MKQT=W NQN wow mowmum m5 QQN A ril 17, 1956 H. A. SILVEN GRINDING MACHINE 6 Sheets-Sheet 4Filed Dec. 1, 1953 INVENTOR. HERBERT A SILVEN BY WLDEa'xa-w ATTURNEYApril 17, 1956 s v 2,741,879

GRINDING MACHINE Filed Dec. 1, 1953 6 Sheets-Sheet 5 [7/ 42 mwszvroa.HERBERT A. 5/Ll/EN I89 770 I72 ATTORNEY Filed Dec. 1. 1953 6Sheets-Sheet 6 Fig.9

INVENTOR.

HERBERT A. 51L VEN uflaumeaxm ATTo ENEY United States Patent 2,141,879GRINDING MACHINE Herbert A. Silven, Worcester, Mass, assignor to NortonCompany, Worcester, Mass., a corporation of Massachusetts ApplicationDecember 1, 1953, Serial No. 395,401

4 Claims. (CI. 51-95) The invention relates to grinding machines andmore particularly to a cylindrical-type grinding machine for grindingwork pieces of relatively large diameters.

One object of the invention is to provide a simple and thoroughlypractical grinding machine for grinding large diameter work pieces.Another object is to provide a grinding machine having an L-shaped baseso as to provide a control station adjacent to the point of contactbetween the grinding wheel and work whereby the progress of the grindingoperation may be readily observed. Another object is to provide acontrol station whereby the longitudinal traversing of the work and thetransverse movement of the grinding wheel may be readily controlledwhile observing the grinding operation. Another object is to provide alongitudinally movable work table with a transversely movable slide tofacilitate a transverse maning mechanism for the work head to facilitateprecise swivelling of the work head relative to the longitudinallymovable carriage and the cross slide. be in part obvious or in partpointed out hereinafter.

In theaccompanying drawings, in which is shown one of various possibleembodiments of the mechanical features of this invention, h

Fig. 1 is a front elevation of the improved grinding machine;

Fig. 2 is a right hand end elevation of the machine;

Fig. 3 is a fragmentary'vertical sectional view, on an enlarged scale,taken approximately on the line 3--3 of Fig. 2, through the work headtraversing mechanism;

Fig. 4 is a fragmentary vertical sectional view, on an enlarged scale,taken approximately on the line 4-4 of Fig. 1, through the drivemechanism for the longitudinal traversing of the work head;

Fig. 5 is a fragmentary elevation, on an enlarged scale, takenapproximately on the line 5-5 of Fig. 3, showing a portion of themanually operable work head traversing mechanism.

Fig. 6 is a fragmentary plan view, on an enlarged scale, with the workhead removed, showing the swivelling mechanism therefor;

Fig. 7 is a fragmentary vertical sectional view, taken approximately onthe line 7--7 of Fig. 6, through the pivot for the work head;

Fig. 8 is a combined hydraulic and electric diagram of the control andactuating mechanisms of the machine; and

Fig. 9 is a plan view of the grinding machine showing the L-shaped base.

A grinding machine has been illustrated in drawings comprising a base 10which supports a wheel slide base 11 (Fig. 2). A transversely movablewheel slide 12 is supported on a V-way 13 and a flat way 14 (Fig. 1)formed on the upper surface of the wheel slide base 11. The wheel slide12 serves as a support for a rotatable Other objects will position.

2,741,879 Patented Apr. 17, 1956 multiple V-belts 20 with a multipleV-groove pulley 21 mounted on the right hand end of the wheel spindle 15(Fig. 1). h

A suitable feeding mechanism is provided for the wheel slide 12comprising a. half-nut 25 depending from the underside of the wheelslide 12. The'half-nut 25 meshes with or engages a rotatable feed screw26 which is journalled in suitable bearings 27 carried by a slidablymounted sleeve 28; The sleeve 28 is supported within a cylindricalaperture formed within the wheel slide base 11. A manually operable anda power operated mechanism are provided for actuating the feed screw 26so as to pro vide a manual adjustment for the wheel slide, a rapidpositioning movement therefor and a grinding feed. This mechanism issubstantially the same as that disclosed in the U. S. Patent No.2,522,485 to H. A. Silven and C. G. Flygare dated September 12, 1950, towhich reference may be had for details of disclosure not containedherein. A fluid pressure cylinder 29 is provided having a slidablymounted piston 30 which is connected. to one endof a piston rod 31. Theother end of the piston rod 31 is connected to the slidably mountedsleeve 28.. The cylinder 29 and the piston 30 are preferably arranged inaxial align ment with the feed serew 26 and are arranged to cause arapid axialmovement of the feed screw 26 rapidly to move the wheel slide12 toward and from an operative A feed control valve 35 is provided forcontrolling the admission to and exhaust of fluid from the cylinder 29.This valve is substantially identical with that shown in the priorpatent to which reference may be had for details of disclosure notcontained herein. 1 The valve 35 is a piston-type valve having a valvestem 36. A com: pression spring 37 surrounding the valve stem 36 servesnormally to hold the valve stem 36 in a right hand end position. Asolenoid 38 is provided which when energized serves to movethe valvestem 36 toward the left to reverse the flow of fluid to the cylinder 29.

A fluid pressure system is provided for supplying fluid under pressurefor the various actuating mechanisms of the machine. This system maycomprise a motor driven fluid pump 40 which draws fluid through a pipe41 from a fluid reservoir 42 and forces fluid under pressure through apipe 43 to the mechanisms of the machine as will be hereinafterdescribed. A relief valve 44 is connected in the pipe line 43 forexhausting excess fluid under pressure from the pipe 43 so as tomaintain the desired operating pressure within the system.

In the position of the valve 35 (Fig. 8), fluid under pressure in thepipe 43 passes through the valve 35 into a cylinder chamber 45 to movethe piston 30 together with the feed screw 26 and the wheel slide 12toward the right, that is, toward a rearward or inoperative position.During this movement fluid within a cylinder chamber 46 may exhaustthrough a passage 47, through a throttle valve 48 and through an exhaustpipe 49 into the resevoir 42. The throttle valve 48 serves to controlthe rate of movement of the piston 30 during its movement to a rearwardor inoperative position. A dash pot mechanism 50 is provided forcushioning the rearward movement of the piston 30 in the end of itsrearward stroke.

A manually operable mechanism is provided foractuating the feed screwcomprising'a manually operable feed wheel (Fig. l) which is operativelyconnected through a gear not shown to rotate a gear 56 mounted on arotatable shaft 57. The shaft 57 also supports a gear 58 which mesheswith a gear 59 mounted on the forward end of a feed screw shaft 60 whichis formed integral with the feed screw 26. it will be readily apparentfrom the foregoing disclosure that a rotary motion of the feed wheel 55will be transmitted through the gear mechanism above described to rotatethe feed screw shaft 60 and the feed screw 26 and thereby impart atransverse feed- 7 ing movement to the wheel slide 12. The directionof'rotation of the feed wheel serving to determine the direction ofmovement of the wheel slide. A pivotally mounted stop pawl 61 is mountedon the front of the machine base and is arranged to be engaged by anadjustable stop abutment 62 carried by the said wheel 55 to facilitate aprecise positioning movement of the wheel slide 12 and the grindingwheel 16 as it is moved toward the work piece to be ground.

A feeding mechanism is also provided for producing a slow precisefeeding movement of the grinding wheel during the grinding operation. Inthe preferred form, a hydraulically operated mechanism is provided sothat the feed screw may be rotated at a controlled rate to cause acontinuous infeeding movement of the grinding wheel. This mechanism maycomprise a fluid pressure cylinder 65 having a slidably mounted piston66. The upper surface of the piston 66 is provided with rack teeth 67which mesh with a gear 68 mounted on a rotatable shaft 69.

The shaft 69 also supports a gear 70 which meshes with the gear 56. Itwill be readily apparent from the foregoing disclosure that when thepiston 66 is moved longitudinally within the cylinder 65 a rotary motionwill be imparted to the feed screw 26. When fluid under pressure ispassed through-a pipe 71 into a cylinder chamber 72, the piston 66 willbe moved toward the right (Fig. 8) to impart a counter-clockwise rotarymotion to the feed wheel 55. During this movement of the piston 66,

fluid within a cylinder chamber 73 may exhaust through a pipe 74.

Similarly when fluid under pressure is reversed and is passed throughthe pipe 74 into the cylinder chamber 73, the piston 66 will be movedtoward the left (Fig. 8) to impart a clockwise rotary motion to the feedwheel 55 thereby imparting a rotary motionto the feed screw 26 in theopposite direction to cause a rearward movement of the wheel slide 12and the grinding wheel 16.

A shuttle-type feed control valve 75 is provided for controlling theadmission to, and exhaust of fluid from the cylinder 65. The valve 75 isa shuttle-type valve having a slidably mounted valve member 76 having aplurality of spaced valve pistons formed integrally therewith. The valvepistons are arranged to form spaced valve chambers 81, 82, 83 and 84.The valve 75 is arranged so that when fluid under pressure is passedthrough a pipe '77 into an end chamber 78, and slidably mounted valvemember 76 will be moved toward the right into the position illustratedin Fig. 8 during this movement fluid within an end chamber 79 isexhausted through a pipe 80. The admission to and exhaust of fluidthrough the pipes 77 and ft) respectively is controlled by the feedcontrol valve 35. In the position of the valve 75, fluid under pressureis passed through the pipe77 to shift the valve member 76 into its righthand end position so that the fluid'under pressure from the pipe 43enters the valve chamber 84, passes through a central aperture 86, intothe valve chamber 82 and through the pipe 74 into the cylinder cham ber73 to move the feed piston 66.1oward the left into the positionillustrated in Fig. 8. During this movement of the piston 66 fluidwithin the chamber 72 may exhaust through the pipe 71, through the valvechamber 81, through the pipe 85 into the exhaust pipe 49 and into thefluid reservoir 42.

When the solenoid 38 is energized to shift the feed control valve 35 toinitiate a rapid forward movement of the wheel slide 12, fluid underpressure is passed through the pipe 80 into the end chamber 79 to shiftthe valve member 76 toward the left so that fluid under pressure passingthrough the pipe 43 will enter the valve chamber S t, pass through thecentral aperture 86, into the valve chamber 82 and through a pipe 71into the end chamber 72 to start movement of the piston 66 toward theright (Fig. 8) thereby starting a rotary motion of the feed screw toadvance the grinding wheel 16 into the work piece being ground for apredetermined grindingoperairon. 1

It is desirable that the backlash in the feed mechanism parts be rapidlytaken up at the start of the infeeding operation. This is preferablyaccomplished by a backlash control valve which is a shuttle type valvecomprising a valve stem 91 having a pair of spaced pistons formedintegrally therewith to form a valve chamber 92. Fluid under pressurepassing through either the pipe 77 or the pipe 80 enters'an end chamber93 or an end chamber 94 respectively to shift the shuttle valve member91 into the opposite end position. During this shifting movement of thevalve member 91, fluid may exhaust from the valve '75 through a pipe 97,through the valve chamber 9'2 andpass substantially unrestricted intothe exhaust line 49 thereby facilitating a rapid movement of the piston66 during its initial movement in either direction to take up thebacklash in the feed mechanism parts. The rate of movement of the valvemember 91 determines the amount of fluid that may be metered from thepipe 97 directly into the pipe 49. A throttle valve 95 is provided inthe pipe line 77 to control the rate of movement of the valve member 91.A check valve 96 is provided so that fluid under pressure may bypass thethrottle valve 95 to cause a rapid movement of the valve member 91toward the right since the elimination of the backlash is of noimportance on the rearward stroke of the wheel slide 12.

A throttle valve 9% is provided to control the normal exhaust of fluidfrom the valve 75. Fuid exhausting from the valve 75 may pass through apipe 98, through the throttle valve 99, through a V-port 101} and intothe ex haust line 49. An actuating knob 101 is provided for regulatingthe valve 99 so as to control the normal rate of movement of the piston66 and thereby control the rate of grinding feed.

A suitable control mechanism is provided for initiating a grinding cyclecomprising a control lever 195 which pivotally supported by a stud 166on the front of the machine base. The lever 105 is provided with a pairof actuating screws 1b? and let; which are arranged to actuate a startswitch 109 or a stop switch ill depending upon the direction of movementof the control lever 105. When it is desired to start a grinding cycle,the control lever 105 is rocked in a clockwise direction (Fig. 8) toclose the start switch 169 thereby energizing an electric timer 111. Theenergizing of the electric timer 111 serves to energize the solenoid 3bto shift the said control valve 35 and thereby start a rapid approachingmovement of the wheel slide 12 and the grinding wheel 16. As abovedescribed when the feed control valve 35 is shifted to start a rapidapproaching movement of the wheel slide 12, fluid under pressure ispassed to the backlash valve 90 and also to the valve 75 to startmovement of the piston 66, first taking up backlash in the feedmechanism parts before the piston 30 reaches the end of its movementtoward the left after which continued movement of the piston rotatingthe feed screw 26, imparts a grinding feed to the wheel slide 12 and thegrinding wheel 16. After a predetermined time interval, the timer 111times-out thereby breakinga circuit to deenergize the solenoid 38 sothat the feed control valve 35 returns to the position illustrated inFig. 8 under the influence of the released compression of the spring 37.The timer 111 may be any of the well known commercial electric timerssuch as for example a Microfiex timer manufactured by the SignalElectric Company of Moline, Illinois. r

The grinding cycle may be terminated at any time if desired by rockingthe control lever in a counterclockwise direction so that the actuatingscrew 108 opens the stop switch 110 thereby deenergizing the timer 111and allowing the parts to return to the initial or inoperative position.

The base 10 also serves as a support for a longitudinally reciprocablework supporting table115 which is slidably mounted on a fiatway 116 anda V-way 117 formed on the upper surface of the base 10. The table 115supports a transversely movable slide 118 which is adjustabletransversely relative to the table 115 by means of a rotatable feedscrew 119. The feed screw 119 is rotatably journalled in bearingscarried by the slide 118. i The feed screw 119 meshes with or engages ahalf-nut 120 mounted on the upper surface of the work table 115. Amanually operable feed wheel 121 is arranged to rotate a gear or pinion122 which meshes with a gear 123 keyed on the forward end of the feedscrew 119 (Fig. 2). readily apparent from the foregoing disclosure thata retary motion of the feed wheel 121 will impart a transverse feedingmovement to the slide 118. The slide 118 serves as a support for aplaten 125 which is pivotally connected thereto by means of a pivot stud126. The platen 125 may be swivelled angularly to facilitate adjustingthe position of the axis of the work piece to be ground relative to theaxis of the grinding Wheel. W

l A pair of clamping bolts 127 and 127a pass through clearance holesformed in the platen 125. The heads of clamping bolts 127 and 127a ridein arcuate shaped T- slots 129 and 129a formed in the upper surface ofthe transversely movable slide 118. A clamping bolt 128 fixed to theslide 118 passes through an arcuate slot 130 formed in the platen 125.The clamping bolts 127, 127a and 128 serve to facilitate clamping theplaten 125 in adjusted position.

A nut and screw mechanism is provided for precisely adjusting theposition of the platen 125' relative to the slide 118 comprising arotatable screw131 which is journalled in a bearing 132 carried by theslide 118. The screw 131 is provided with a manually operable actuatingwheel 133. The feed screw 131 meshes with or engages a nut 134 carriedby the platen 125. It will be readily apparent from the foregoingdisclosure that a rotary motion of the wheel 133 will impart aswivelling movement to the platen 125.

A rotatably mounted work supporting spindle 135 is journalle'd inbearings (not shown) carried by a work head which is adjustably mountedon the platen 125. A work supporting chuck or face plate 136 is mountedon the right hand end of the spindle 135 (Fig. 1). A suitable drivingmechanism is provided for the work spindle 135 comprising an electricmotor 137 adjustably mounted on the top of the work head. The motor 137is provided with a stepped multiple V-groove pulley 138 which isconnected with multiple V-belts 139 with a multiple V-groove pulley 140mounted on a shaft 141. The shaft 141 is connected by. a coupling withdrive shaft 141a of a speed reducer unit 142. A driven shaft 143 of thespeed reducer unit 142 is provided with a multiple V-groove pulley 144which is connected by multiple V-belts 145 with a multiple V-groovepulley 146 mounted on the left hand end of the work spindle 135 (Fig.1).

The work table 115 is arranged so that it may be ad justedlongitudinally or reciprocated or traversed longitudinally by means of anut and screw mechanism comprising a rotatable screw 150 which isjournalled in antifriction bearings 151 and 152 (Fig. 3) which aresupported in fixed relation relative to the base 10. The feed screw 150meshes with or engages a nut 149 depending from the under side of thetable 115. A sprocket 153 is mounted on the left hand end of the feedscrew 150 and is connected by a cog-belt 154 with a sprocket 155 mountedon a shaft 156 of a fiuid motor 157 which is fixedly supported on thebase 10 of the machine. An idler pulley 158 serves to tension the belt154 as desired. The cog-belt 154 is preferably a commercially well knownbelt, such as, the Gilmer timing belt.

A suitable control mechanism is provided for the fluid motor 157comprising a manually operable start-stop valve 160 which is preferablya rotary-type valve actuated by a manually operable handle 161. Thevalve 160 is arranged when in a start position to pass fiuid throughfrom the pipe 43, through the valve 160 and through a pipe 162 to ashuttle-type control valve 163. When the valve 160 is in the positionillustrated in Fig. 8, fluid may exhaust from the valve 163, through thepipe 162, through the valve 160 and through a pipe 164 into the exhaustpipe 49 and the reservoir 42.

It will be The shuttle-type control valve 163 is a piston-type valve 171is connected with the end chamber 172 by a throttle valve 175 and acheck valve 176 which are arranged so that fluid under pressure may bepassed unrestricted from the pipe 171 into the end chamber 172. Fluidexhausting from the end chamber 172 is controlled by the throttle valve175. Similarly the pipe 174 is connected by a throttle valve 177 and acheck valve 178 with the end chamber 173. The check valve 178 isarranged. so that when fluid under pressure is passed through the pipe174 it may pass substantially unrestricted into the end chamber 173.Fluid under pressure exhausting from the end chamber 173 is governed bythe throttle valve 177. It will be readily apparent from the foregoingdisclosure that by manipulation of the throttle valve 175 and 177, therate of shifting of the valve member 165 in either direction may beregulated as desired.

A table actuated reversing valve 180, is: provided for controlling theadmission to and exhaust of fluid from the valve 163. The valve 180 is arotary-type valve which may be actuated manually by means of a manuallyoperable handle 181 or may be actuated automatically by a pair of offsetradially projecting studs 182 and 183 which are arranged in the path ofa pair of adjustable table dogs 185 and 186 respectively. In theposition of the valve 180 (Fig. 8) fluid from the pipe 43 passes throughthe valve 180 and through the pipe 171 into the end chamber 172 to movethe valve member 165 toward the left at a rate controlled by thethrottle valve 177. When the start-stop valve 168 is in a traverse orstart position, fluid under pressure passing through the pipe 162 entersthe valve chamber 170 and passes through a pipe 187 to the fluid motor157 to start the motor rotating in one direction to cause a longitudinaltraversing movement of the work table 115. During this movement fluidmay exhaust from the other side of the motor 157 through a pipe 188 intothe valve chamber 169, through a pipe 189 into the exhaust pipe 49 andthe reservoir 42. A

throttle valve 190 is provided in the pipe 189 to facilitate.

controlling the rate of exhaust of fluid from the motor 157 thereby tocontrol the rate of traversing movement of the table 115. A check valve191 is provided in the pipe 189 so that fluid may bypass around thethrottle valve 198 when fluid is passed in the opposite direction.

As shown in Fig. 1 the table 115' when started will move in a directiontoward the left as above described. This movement toward the left willcontinue until the dog 186 engages the stud 182 to shift the valve 180in a counter-clockwise direction so that fluid under pressure from thepipe 43 will pass through the valve 180 and through the pipe 174,through the check valve 178 into the end chamber 1.73 to shift the valvemember 165 toward the right at a rate controlled by the throttle valve175. With the valve member 165 in its right hand end position fluidunder pressure from the start-stop valve 160 passing through the pipe162 enters the valve chamber 169 and passes through the pipe 188 to themotor 157' to rotatethe motor in the reverse direction thereby startingthe table 115 moving in a direction toward the right (Fig. 1). Duringthis movement fluid may exhaust from the motor 157 through the pipe 187,into the valve chamber 174), through the pipe 139, the throttle valve194 into the exhaust pipe 49 and the reservoir $22.

A manually operable mechanism is provided for actuating the screw 15!)to facilitate a manual traversing movement of the table 115. Asillustrated in Fig. 3, a manually operable traverse wheel 26% is keyedon the right hand end of a shaft 2%1 which is journalled in bearings and293 carried by a casing 2M. The shaft Ziill is provided with a gear 265which is arranged to be moved axially into or out of engagement or meshwith a gear 296. The gear 2% is supported by a stud 2t fixedly mountedwithin the casing 2%. The gear 2% meshes with a gear 2% which is keyedon the right hand end of a shaft 2&9. The shaft ass is journalled in anantifriction bearing at its right hand end. The left hand end of theshaft 299 telescopes over a reduced end portion 21.1 of the feed screw15% and is keyed thereto. The casing 29 is preferably adjustably mountedso that the casing together with the traversing wheel 2% may be swung ina transverse direction so that it may be maintained in close proximityto the feed wheel 55. A flange member 212 is fixedly mounted relative tothe base 10 and is provided with a. pair or elongated arcuate slots 213and 214. A pair of clamping bolts 215 and 216 pass through the elongatedslots 213 and 214 respectively and are screw threaded into the casing294.

This machine is particularly intended for grinding relatively largediameter work pieces which may be mounted on a face plate or chuck forgrinding peripheral faces or side faces thereon. It is desirable in agrinding operation of this type that the operator be able to visiblyobserve the grinding operation as it proceeds. By the provision of thesubstantially l shaped base, a control station is provided whereby theoperator may readily observe the grinding action of the grinding wheel16 and may readily control actuation of the feed wheel 55, the traversewheel 2%, the cycle control lever ms and the traverse control valve 160while observing the grinding operation. As previously stated the casing264 is adjustably mounted so that it may be swung about the ax' of thefeed screw 159 so that the traverse control wheel Ztitl may bepositioned in a convenient location relative to the feed wheel 55,

The operation of this improved grinding machine will be readily apparentfrom the foregoing disclosure. A

workpiece to be ground is mounted on the face plate .136, the wheeldrive motor is then started and the motor for driving the pump id isstarted after which a grinding cycle may be started by actuation of thecontrol lever 165. For a plunge cut grinding operation the table orcarriage 115 remains stationary while the grinding wheel slide 12 is fedtoward the periphery of the work piece to grind the same to the desiredand predetermined extent. The grinding cycle may be under the control ofthe timer 111 or if desired may be manually controlled by reciprocatedby power in a manner above described as controlled by the valve 160, ormay if desired be manually. controlled by actuation of the traversingwheel 200.

It will thus be seen that there has been provided'by this inventionapparatus in which. the various objects herei, above set forth togetherwith many thoroughly practical advantages are successfully achieved. Asmany embodiments may be made of the above invention and as many changesmight be made in the embodiments above set forth, it is to be understoodthat all matter hereinbefcre set forth, or shown in the accompanyingdrawings,

is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a grinding machine having a substantially L- shapcd base, atransversely movable wheel slide slidably supported toslide transverselyon a longitudinally extendr ing portion of the base, a rotatablegrinding wheel thereon, a nut and screw feed mechanism interposedbetween the slide and base, means including a manually operable feedwheel rotatably supported on the front of said longitudinally extendingbase portion to actuate nut and screw mechanism, a longitudinallymovable carriage slidably supported on the forwardly projecting portionof said base, said carriage being arranged to slide in a directionnormal to the transverse movement of the wheel slide, a rotatable worksupport on said carriage, means including a power operated traversingmechanism interposed between said carriage and base, and a manuallyoperable traverse wheel rotatably supported on the side of saidforwardly projecting base portion which is operatively connected toactuate said traversing mechanism, a movably mounted casing adjustablysupported on the end of the longitudinally movable carriage forsupporting said manually operable traverse wheel, and means to adjustsaid casing so as to vary the position of said traverse wheel relativeto the feed wheel.

2. in a grinding machine having a substantially L- shaped base, atransversely movable wheel slide slidably supported to slidetransversely on a longitudinally extending portion of the base, arotatable grinding wheel thereon, a nut and screw feed mechanisminterposed between the slide and base, a manually operable feed wheelrotatably supported on the front of said longitudinally extending baseportion operatively connected to actuate said nut and screw mechanism, alongitudinally movable carriage slidably supported on a forwardlyprojecting portion of the base, said carriage being arranged to slide ina direction normal to the movement of said slide, a rotatable worksupport on said carriage, means including a power actuated nut and screwtraversing mechanism interposed between the carriage and base, and amanually operable traverse wheel rotatably supported on the side of saidforwardly projecting base portion which is operatively connected toactuate said traversing screw, a pivotaliy mounted easing adjustablysupported on the end of the longitudinally movable carriage forsupporting said manually operable traverse wheel, and means toadjustably swing said casing so as to vary the position of said traversewheel relative to said feed wheel, said L-shaped base serving to providea control station in close proximity to the grinding wheel and therotatable work support whereby the feed wheel and traverse wheel may bereadily actuated while visibly observing the grinding action of thegrinding wheel upon the work piece being ground.

3. In a grinding machine as claimed in claim 1, in combination with theparts and features therein specified of a transversely movable slideslidably mounted on said carriage, means including a manually operablenut and screw mechanism interposed between the carriage and slide tofacilitate a transverse adjustment of the slide relative to thecarriage, a work head supported on said slide, a rotatable work spindlerotatably supported, on the work head having a work supporting member,pivotal connections between said slide and head including a verticallyarranged pivot stud interposed therebetween, and precision meansincluding a manually operable nut and screw mechanism interposed betweenthe slide and work head to facilitate precisely swivelling the work headrelative to the slide.

4, In a grinding machine as claimed in claim 2, in combination with theparts and features therein specified of means including a rotary-typefluid motor operatively connected to rotate said work carriagetraversing screw, means including a fluid pressure actuated reversingvalve operatively connected to control the admission to and exhaust offluid from said fluid motor, a pilot valve operatively connected toactuate said reversing valve, and means including adjustable dogs onsaid carriage to actuate said pilot valve to facilitate controlling thereciprocatory stroke of the work carriage.

References Cited in the file of this patent UNITED STATES PATENTS423,243 Handloser Mar. 11, 1890 1,073,487 Hinds et al. Sept. 16, 19132,127,210 Dunbar Aug. 16, 1938 2,522,485 Silven et al. Sept. 12, 1950

